The invention relates to a disposable device for carrying out a process in which a biological sample is processed with one or more reagents.
The invention relates in particular to a disposable device which is suitable for carrying out a process for obtaining a purified nucleic acid sample from a biological sample.
The invention further relates to use of such a device for processing a fluid biological sample with one or more reagents in order to obtain a purified nucleic acid sample.
Known methods for obtaining a purified nucleic acid sample suitable to be amplified, by, for example, a polymerase chain reaction (PCR) are usually carried out manually and involve a number of steps and in particular a plurality of pipetting operations. Since contamination of the purified sample to be obtained has to be reduced as far as possible, the manual process has to be carried out with great care and is therefore a time consuming task.
Known apparatus for automatically carrying out pipetting operations in analyzer systems have been found inadequate for methods aiming to obtain purified nucleic acid samples suitable to be amplified, such as by a polymerase chain reaction (PCR), because contamination of the sample is likely to occur during pipetting operations.
A main object of the invention, therefore, is to provide a device to ensure a contamination-free automatic processing of samples and reagents to a degree which is sufficient to comply with the requirements of nucleic acid purification methods which provide nucleic acid samples having a high degree of purity and being thereby suitable to be amplified.
According to a first aspect of the invention, this problem is solved by a disposable process device which comprises an array of chambers integrally connected to each other, a cover insert removably connected to the array of chambers, and a disposable pipetting tip.
The integrally built array of chambers comprises an upper part shaped as an elongated tray and having an interior delimited by a bottom wall and a side wall which extends perpendicular to and along the perimeter of the bottom wall; a first process chamber having an open top end and a closed bottom end connected by a tubular wall which extends substantially perpendicular to the bottom wall of said upper part and downwardly from a first opening in said bottom wall, said first opening forming the open top end of the first process chamber; and a waste chamber for receiving waste liquids, said waste chamber having an open top end and a closed bottom end connected by a side wall which extends substantially perpendicular to the bottom wall of said upper part and downwardly from a second opening in said bottom wall, said second opening forming the open top end of the waste chamber.
The cover insert is configured and dimensioned to be inserted in the chamber array and the cover insert comprises an elongated cover having openings providing access to the process chamber and the waste chamber respectively when said cover insert is inserted in said chamber array; and a parking chamber for parking therein said disposable pipetting tip, said parking chamber having an open top end and a closed bottom end connected by a tubular wall which extends substantially perpendicular to the cover and downwardly from an opening in the cover.
The disposable pipetting tip is configured and dimensioned to be at least partially inserted in the interior of the parking chamber.
According to a second aspect of the invention, the contamination-free automated processing of samples and reagents is attained by using a device according to the invention for carrying out a process wherein a fluid biological sample is processed with one or more reagents. This process comprises steps of automatic transfer of liquids from a process chamber to the waste chamber, or from a primary sample tube external to the device to the first process chamber, or from a process chamber to a specimen container external to the device, and wherein said transfer of liquids is effected by means of pipetting operations carried out exclusively with the disposable pipette tip which is part of the device.
The main advantage of the device and of the process according to the invention is that they make possible a contamination-free automatic processing of samples and reagents to a degree which is sufficient to comply with the requirements of nucleic acid purification methods which provide nucleic acid samples having a high degree of purity and being thereby suitable to be amplified, such as by a polymerase chain reaction (PCR).
A further advantage of the device according to the invention is that a plurality of these devices can be used simultaneously in an automatic apparatus to obtain a corresponding plurality of purified nucleic acid samples from respective biological samples.
A specific advantage of an embodiment of the device according to the invention comprising only one process chamber is that it is cheaper than a device comprising more than one process chamber, and that the small size of the device contributes to less waste material which must be disposed of after use of the device, and it reduces the cost of packaging material therefor.
A preferred embodiment of the device according to the invention is characterized in that the cover comprises a first channel which provides access to the interior of the process chamber for dispensing a liquid into this chamber. This dispensing is typically effected with a pipetting cannula other than the disposable pipetting tip. The advantage of this embodiment is that the channel mentioned ensures that during the pipetting operation the tip of the pipetting cannula is located within a substantially closed environment which prevents accidental contamination during the transfer of liquid from the pipetting cannula to the process chamber.
A further preferred embodiment of the device according to the invention is characterized in that a substantial part of the parking chamber is located within the waste chamber when said cover insert is inserted into said array of chambers. This configuration advantageously reduces the space occupied by the device, because no additional space is necessary for the parking chamber.
In another preferred embodiment of the device according to the invention, the process chamber depends freely downwardly from the bottom wall of said upper part of chamber array. This configuration offers the advantage that the lower part of the process chamber is accessible to external means, e.g. magnets, used to obtain separation of magnetic particles in suspension in a liquid contained in the process chamber.
A further preferred embodiment of the device according to the invention is characterized in that the integrally built array of chambers further comprises a second process chamber having an open top end and a closed bottom end connected by a tubular wall which extends substantially perpendicular to the bottom wall of said upper part and downwardly from a third opening in said bottom wall. The third opening forms the open top end of the second process chamber. The advantage of this embodiment is that it offers more flexibility with regard to the sequence of process steps for carrying out a particular method. This flexibility is increased e.g. by maintaining the process chambers at different temperatures, e.g. one at 60xc2x0 C. and the other at 37xc2x0 C., or by using one of the process chambers for provisional storage of a reagent before it is transferred to the other process chamber.
A preferred embodiment of the device according to the invention and comprising two process chambers is characterized in that the bottom wall of said upper part comprises a second channel which provides access to the interior of the second process chamber for dispensing a liquid into this chamber. This dispensing is typically effected with a pipetting cannula other than the disposable pipetting tip. The advantage of this embodiment is that the second channel ensures that during the pipetting operation the tip of the pipetting cannula is located within a substantially closed environment which prevents accidental contamination during the transfer of liquid from the pipetting cannula to the second process chamber.
Another preferred embodiment of the device according to the invention and comprising two process chambers is characterized in that the first process chamber, the waste chamber and the second process chamber are arranged in a row. This linear configuration advantageously simplifies the arrangement of a plurality of devices according to the invention in an automatic processing apparatus and also the transport means used for moving the disposable pipetting tip and the pipetting cannula to their pipetting positions with respect to the various chambers of the device.
Another preferred embodiment of the device according to the invention and comprising two process chambers is characterized in that the waste chamber is located between the first process chamber and the second process chamber. This configuration advantageously reduces the motion paths of the disposable pipetting tip and the pipetting cannula necessary to bring these to their pipetting positions with respect to the various chambers of the device.
A further preferred embodiment of the device according to the invention and comprising two process chambers is characterized in that the second process chamber depends freely downwardly from the bottom wall of said upper part of chamber array. This configuration offers the advantage that the lower part of the second process chamber is accessible to external means, e.g. magnets, used to obtain separation of magnetic particles in suspension in a liquid contained in the second process chamber.
Preferred embodiments of the device according to the invention are characterized in that the array of chambers of the device according to the invention is a single piece of plastic material.
Preferred embodiments of the device according to the invention are characterized in that said cover insert of the device according to the invention is a single piece of plastic material.
These preferred embodiments make it possible to reduce the manufacture price of the device.
A preferred use of the device according to the invention is for carrying out a process characterized in that it comprises steps of dispensing a liquid reagent from a reagent container external to the device into the process chamber, said dispensing being effected with a pipetting cannula other than the disposable tip which is part of the device.
A preferred use of the device according to the invention and comprising two process chambers is a process which comprises the steps of automatic transfer of liquids from the first process chamber into the second process chamber or vice versa, or from the first or the second process chamber to the waste chamber, or from a primary sample tube external to the device to the first or the second process chamber, or from the first or the second process chamber to a specimen container external to the device, and wherein said transfer of liquids is effected by means of pipetting operations carried out exclusively with the disposable tip which is part of the device.
A further preferred use of the device according to the invention and comprising two process chambers is a process which comprises the steps of dispensing a liquid reagent from a reagent container external to the device into the first process chamber or the second process chamber, said dispensing being effected with a pipetting cannula other than the disposable tip which is part of the device.
A preferred use of the device according to the invention is a process for isolating a nucleic acid contained in a biological sample.